Motor operated mechanism



March 26, 1940. w. J. McGoLDRlcK 2,195,219

MOTOR OPERATED MEGHANISM Filed Nov.. l2, 1938 *la 'HO 912 1(7\ vI'// /q 48 :i 50 [A a9 Sq 5s fo A s? q/TIQWMLH 1 T w88 56 q2 4 Cttorngg nvmfor Patented Mar. 26, 1940 UNITED ISTATES A PATENT OFFICE MOTOR OPERATED MECHANISM William J. McGoldrick, Minneapolis, Minn., as-

signor to Minneapolis-Honeywell Regulator Company, Minneapolis,`Minn., a corporation of Delaware Application November 12, 1938, Serial No. 239,977

11 Claims.

mined period of time after the motor has been placed in operation.

A further object of the present invention is to i provide an arrangement such as set forth in the previous object in which the means for causing reengagement of the clutch comprises an electrically energized heat motor electrically connected in the energizing circuit of the motor.

) A further object oi.' the present invention is to provide an arrangement such as set 4out in the previous objects in which the clutch is normally vheld disengaged by a temperature responsive device which upon operation of the motor is heated 5 to cause engagement of the clutch.

A still further object is to provide such an arrangement in which the rotor of the motor is effective upon energization 'of the motor to engage the clutch and in which the temperature respon- I` sive device acts when subjected only to ambient temperatures to disengage the clutch.

A further object of the invention is to provide such an arrangement in which the temperature responsive device is of the snap acting type.

"I, A further object of the present invention is to employ the arrangement of the previous objects in connection with a device biased to one position so that upon disengagement of the clutch, the biasing means is able jto move the device to its I biased position independently ofthe motor.

Other objects will be'apparent from a consideration of the accompanying speeiiication, claims, and drawing in which:

Figure l is a schematic view of the motor opcrated mechanism of the present invention employed in connection with a valve controlling the ow of a temperature changing medium, and

Figure 2 is a schematic view of the motor portion of a modified form of the mechanism.

u As indicated above, the drawing illustrates the invention ,employed in connection with a valve I controlling the flow of a temperature changing medium. The valve is shown as comprising a valve casing having the usual aperture partition wall |2 upon which seats a valve disc I4.

The valve disc |4 controls the flow of fluid between the inlet I5 and the outlet I8. Secured to the valve disc I4 is a valve stem I 8 which extends through a valve stem guide |9 which, in turn, extends through a closure plate 2|. 'I'he closure plate 2| is secured to the valve casing I I by means of a flanged nut 22. Secured to the closure plate 2| is a motor supporting base member 24, to which the guide |9 is secured. 'Ihis base member supports the motor mechanism which in a commercial form of the device would be compactly' housed in a suitable casing. In the drawing, this motor mechanism is shown in schematic form for clarity of illustration.

The valve stem I8 carries a spring retainer 29. Interposed between this spring retainer 29 and the closure plate 2| is a spring 30. The spring 30 serves to bias the valve disc I4 into closed position.

Pivotally secured to the upper end of the valve stem I8 is a lever 3|. The lever 3| is pivotally mounted on a suitable supporting structure at 32. Pivotally secured to the right-hand end of lever 3| is a link 33 which is provided atA its upper end with a hook 34. Hook 34 lies in the path oi' and is adapted to be engaged by a pin 35 carried by a gear 36. The gear 36 is the low speed'gear of a reduction gear train generally designated by the reference numeral 31. The high speed end' of the gear train is connected to a pinion gear 38 slidably and rotatably supported on the shaft 39 oi.' a motor generally indicated by the reference numeral 40. H

Motor 40 is shown as being of the induction type, comprising astator core structure 42 on which are located field coils 43 and 44. A rotor 45 is carried by the shaft 39, which shaft is sup- 48 is moved to the left is adapted to engage a drive pin 5| secured to and projecting from the pinion gear 38. The motor is illustrated with the drive bar 50 disengaged from the drive pin 5|. When the field windings 43 and 44 are energized, the rotor tends to moveto a position in which it is centrally disposed with respect to the eld. Such movement shifts the shaft 39 axially and brings the drive bar into the path of the drive pin 5|.

This axial shifting of shaft 39 by the rotor 45 is prevented, when the motor is deenerglzed, by a bimetallic element 54 carried by a bracket 56 secured to the stator core 42. 'I'he bimetallic element 54 is shown in its cold position and, as

indicated by the legend, has its upper end deiiected to the left upon temperature rise. Located adjacent the bimetal 54 is an electric heater 55 which is used to heat the bimetal 54 when it is desired to permit axial movement of the shaft 38. As will be discussed in more detail later, the heater 55 is in series with the motor field windings 43 and 44 so that the heater is energized whenever the motor is energized.

As previously indicated, the hook 34 of link 33 is adapted to be engaged by the pin 35 carried by gear 36. When the clutch formed by the drive bar 58 and drive pin 5| is engaged, the energized rotation of motor 48 is effective to rotate gear 36 in a counter-clockwise direction as indicated by the arrow thereon. A coil spring 51 serves to bias the link 33 in a clockwise direction into engagement with pin 35 so that it is assured that the hook 34 will be in the path of pin 35. The resulting upward movement of link 33, as the result of the engagement of pin 35 therewith, causes lever 3| to be rotated about pivot 32 in a counter-clockwise direction to move valve stem |8 upwardly and open valve |8.

The left-hand end of lever 3| is provided with a plurality of openings 58. These openings are intended to facilitate the fastening to the lever 3| of a chain 59 or similar device which is connected t0 a damper 68. The damper 68 is shown as pivotally supported at 6| to a suitable supporting wall 62. rI'he damper 68 is biased downwardly towards open position and upon lever 3| being moved in a counter-clockwise direction, as previously described, damper 68 is permitted to open. Where the valve I8 controls the iiow of gas to a gas burning furnace, the damper 68 is used as a secondary air damper to control the iiow of secondary air to the burner.

The gear 36 is secured to a shaft 65, which shaft is shown in dotted lines except at its intersection with the elements secured thereto. Secured to the left-hand end of shaft 65 is a cam 66. The cam 66 is not rigidly secured to shaft 65 but is secured thereto by what is known as a slip friction connection. In other words, the cam 66 is merely frictionally secured to shaft 65 so that unless the movement of cam 66 is restricted, rotation of shaft 65 will result in rotation of cam 66. Any restriction in the movement of cam 66 will, however, result in cam 66 slipping with respect to shaft 65. The left-hand end of the cam 66 is provided with a recessed portion 61 and a pin 68 is disposed so as to selectively engage the opposite walls of the recessed portion 61. This pin 68 serves to limit the movement of cam 66. Thus in the position shown, a counterclockwise movement of shaft 65 will result in limited movement of cam 66 until the pin 68 is in engagement with the upper wall of the recess 61. Thereafter the cam 66 will merely slip on shaft 65. Immediately upon the reverse movement of shaft 65, the cam 66 will start moving in the reverse direction until the pin 68 again engages the lower wall of the slot. It will be seen that the characteristics of this slip friction connection are that the movement of the operated device is restricted to a relatively narrow range and occurs immediately upon reversal of the driving member. The camy 66 is adapted to actuate a switch blade 18, which switch blade cooperates with a switch blade 1|, both blades being carried by an insulating block 12. The switch including switch blades 10 and 1| is used to establish a maintaining circuit for the motor, as will be subsequently described.

In view of the showing of the invention in connection with a temperature control system, the main control switch has been shown in the form of a room thermostat designated by the reference numeral 15. This thermostat is of conventional construction, comprising a bimetallic element 16 to which is secured a flexible contact arm 11 and a relatively rigid contact arm 18. Contact arms 11 and 18 are adapted to cooperate with contacts 18 and 88, respectively. The contact arm 18 .is more widely spaced from contact 88 than contact arm 11 is from contact 18. The bimetallic element 16 is so disposed that upon temperature fall the contact arms 11 and 18 are moved to the left. It will be obvious that upon such a decrease in temperature, contact arm 11 Will first engage contact 18 and subsequently contact arm 18 will engage Contact 88.

Low voltage power for operation of the system is obtained from a step-down transformer generally designated by the reference numeral 82. This transformer comprises a low voltage secondary 83 and a line voltage primary 84. The line voltage primary 84 is connected to some suitable source of power (not shown).

Operation The various elements are shown in the position which they occupy when the temperature to which thermostat 15 is subjected is at or above the desired temperature. Let it be assumed that the temperature gradually falls. Such drop in temperature will cause engagement first of contact arm 11 with contact 18 and then oi' Contact arm 18 with contact 88. Engagement of contact arm 11 with contact 18 has no effect. As soon, however, as contact arm 18 engages contact 88 an energizing circuit is established to the motor field windings 43 and 44 and the heater 55 as follows: from the right-hand terminal of secondary 83 through conductor 86, contact 18, contact arm 11, contact arm 18, contact 88, conductors 81 and 88, heater 55, conductor 88, field winding 44, conductor 88, field winding 43, and conductor 92 to the other terminal of secondary 83.

The establishment of the above traced circuit results in rotation of the rotor and also in the energization of the heating element 55. The rotation of rotor 45 has no immediate eii'ect upon the position of the valve inasmuch as -the bimetal 54 is in its cold positionand holds the clutch consisting of the drive bar 58 and drive pin 5| in its disengaged position. At the same time, the magnetic field created by the field windings 43 and 44 is tending to pull the rotor 45 into a position in which the electromagnetic center of the rotor is opposite the electromagnetic center of the field, in which position the drive bar 58 and the drive pin 5| are engaged. As the heater heats up the bimetal 58, the portion of the bimetal bearing against shaft 38 is deflected to the left allowing the shaft 53 to move to the left. After this heating has continued for a predetermined period of time, the bar 58 will engage the pin 5| and the rotation of the rotor will be imparted to the gear train. It will be noted that there is a delay between vthe energization of the rotor and the connection of the same with the load. This delay is extremely desirable inasmuch as it gives the motor an opportunity to acquire full running speed before being connected to the load.

The connection of the rotor 45 to the gear train will result in shaft 65 being rotated in a.

counter-clockwise direction. After an initial amount of such rotation, the cam 66 will engage the switch blade 19 moving the same into engagement with switch blade 1l. The engagement of switch blades 10 and 1I results in the establishment of the following maintaining circuit: from the right-hand terminal of secondary 33 through conductor 36, contact 19, contact arm 11, bimetal 16, conductor 93, switch blades 1| and 10, conductors 94 and 83, heating ele- Ament 55, conductor 99, field winding 44, conductor 90, field winding 43, and conductor 92 to the other terminal of secondary 33. It will be noted that this circuit is independent of contacts 19 and 30 so that the motor and heater are not deenergized until the temperature has risen sufliciently to cause disengagement of contact arm 11 from contact 19. This results in the necessity of a temperature differential between the starting and stopping of the apparatus and eliminates any tendency towards a chattering operation, such as might occur' when the thetrnostat rst engaged or disengaged its con- The vrotation of gear 36 in a counter-clockwise direction causes pin 35 lto engage the hook 34 of link 33 and rock lever 3l in a clockwise direction about pivot point 32, as previously explained. This counter-clockwise movement of lever 3l imparts an upward movement to valve stem 80 and consequently to valve disc i4 against the action of biasing spring 39. The counterclockwise movement of lever 3| also` results in the damper 90 being moved to open position.-

Where the system is used in connection with a gas burning furnace, the opening of valve I0 and the damper 60 results in fu'el and secondary air being supplied to the burner.

When the valve reaches open position, the motor is stalled and as long as the motor is energized,

it continues to hold the valve open. It will be apparent that the maintenance of the valve in open position depends upon the. continuance of power for operation of the motor and in the event of power failure the valve will automatically be moved to closed position by the action of biasing spring 30. This type of valve is highly desirable from the safety standpoint inasmuch as it does not require an electrical circuit to close the valve and insures that during power failure the valve will go to the safe position. This type of valve,

however, has the disadvantage that the continued stalling of the motor may tend to slightly overheat the same and cause the bearings to become slightly sticky. If the bearings tend to bind even slightly, the resistance offered to turning of the rotor may be sufiicient to prevent theA spring 30 from moving the valve to closed position since the rotor is at the high speed end of the speed reducing mechanism and obviously a very slight force applied at the high speed end will result in a considerable retarding force at the low speed end.

The presentinvention contemplates the provision of means whereby if the motor does tend to resist rotation thereof, the valve will still be moved to closed position. Let it be assumed that the temperature rises sufficiently to cause disengagement of contact arm 11 from contact 19 so as to result in the deenergization of both the heater 55 and the field windings 43 and 44. The bimetallic element 54 now begins to cool and as it cools it moves shaft 39 to the right. When it has cooled sufficiently, the drive vbar -59 is moved out of engagement with driveipin 5I so that the gear train is again disconnected` from the rotor. The spring 39 is now able to readily Species of Figure 2 In some instances, it may be desirable to have the rotor abruptly engage and disengage with the load at the end of the predetermined period of time required for heating orcooling. In the species of Figure 2, the arrangement is shown wherein the motor is moved in this manner. Inasmuch as all of the elements are identical with the exception of the bimetallic element and the means for supporting the same, the same reference numerals have beenv applied to the other elements. In view of their similarity, it is not believed that further description of these elements will be necessary.

-Secured to the stator core 42 are two bracket members 96 and 91. These bracket members'are provided with resilient V-shaped extensions 93 and 99, respectively. Yieldabiy mounted between these resilient extensions 93 and 99 is a disc |00 of bimetal which is slightly cup shaped to give a snap action. Such elements are well known and need no detailed description. The element |90 is shown in its cold position. As the element is heated up by the action of heater 55, a point will eventually be reached at which this element will abruptly snap over center permitting the engagement of drive bar 50 with drive pin 5 I.

Similarly, vwhen the heater 55 is deenergized the disc |00 will continue to cool until it is able to snap back to the position shown in the drawing, in which position drive bar 50 and drive pin 5l will disengage. The species of the present invention has the advantage that the clutch is abruptly engaged and disengaged and that there is no period in which the drive bar 50 is just touching the drive pin 5| being rapidly moved past the same Without actually moving the pin 5I. In other words, with the arrangement of Figure 1 there is apt to be a period during which the pin 50 is periodically struck against pin 5I creating a vdisagreeable noise. In the arrangement of Figure 2, this is entirely overcome since the bar 50 is moved into the path of the pin 5| very quickly.

While I have shown certain specific embodiments of my invention, it is to be understood that these are for purposes of illustration only and that my invention is limited only by the scope of the appended claims.

I claim as my invention:

1. In combination, an electrical motor, a device to be operated thereby, means including a normally disengaged clutch for connecting said motor and said operated device, means for controlling the energization of said motor, and means including an electrically energized heat motor electrically connected in the energizing circuit of said motor, said last named means being operdevice to be operated by said motor; means including a clutch for connecting said motor and said operated device, said clutch comprising two cooperating elements one of which is connected to the rotor and which the rotor tends to move into engagement with the other element upon energization of said electrical windings; means normally effective to bias said rotor to a position in which said clutch .elements are disengaged; and means effective upon energization of said motor windings to render said biasing means ineffective after the duration of a predetermined period of time.

3. In combination; an electric motor comprising electrical windings, a stator, and a rotor; a device to be operated by said motor; means including a clutch for connecting said motor and said operated device, said clutch comprising two cooperating elements one of which is connected to the rotor and which the rotor tends to move into engagement with the other element upon energization of said electrical windings; temperature responsive means effective when subjected only to the ambient temperature to bias said rotor to a position in which said clutch elements are disengaged; and means effective upon energization of said motor windings to heat said temperature responsive means to render the same ineffective to bias said motor.

4; In combination; an electric motor comprising electrical windings, a stator, and a rotor; a device to be operated by said motor; means including a clutch for connecting said motor and said operated device, said clutch comprising two cooperating elements one of which is connected to the rotor` and which the rotor tends to move into engagement with the other element upon energization of said electrical windings; temperature responsive means leffective when subjected only to the ambient temperature to bias said rotor to a position in which said clutch-elements are disengaged; and an electrical heater adjacent said temperature responsive means, said electrical heater being connected in the same energizing circuit as said electrical windings and being effective upon energization f said electrical windings to render said temperature responsive means ineffective to bias said rotor,

5. In combination, a motor, a device lto be operated thereby, means including a clutch for connecting said motor and said operated device, said clutch including a pair of elements adapted to be interengaged, means tending to move said elements into engagement, temperature responsive means effective when subjected only to the ambient temperature to rove said clutch elements out of engagement, means controlling the operation of the motor, and means effective upon said motor being placed in operation to heat said temperature responsive means to render the same ineffective to move said clutch elements out of engagement.

6. In combination, an electrical motor, a device to be operated thereby, means including a clutch for connecting said motor and said operated device, said clutch including a pair of elements adapted to be interengaged, means tending to move said elements into engagement, temperature responsive means effective when subjected only to the ambient temperature to move said clutch elements out of engagement, means controlling the energization of the motor, and an electrical heater adjacent said temperature responsive means, said electrical heater being connected in the same energizing circuit as said motor and being effective upon energization of said motor to heat said temperature responsive means to render the same ineffective to move said clutch elements out of engagement.

7. In combination, a motor, a device to be operated thereby, means including a clutch for connecting said motor and said operated device, said clutch including a pair of elements adapted to be interengaged, means tending to move said ,elements into engagement, snap acting temperature responsive means effective when subjected only to the ambient temperature to move said clutch elements out of engagement, means controlling the operation of the motor, and means effective upon said motor being placed in operation to heat said temperature responsive means to render the same abruptly ineffective to move said clutch elements out of engagement after a predetermined period of time.

8. In combination, an electrical motor, a device to be operated thereby, means biasing said device to a first position, means including a normally disengaged clutch for connecting said motor and said operating device, said motor being effective when energized and when said clutch is engaged to move said device against the action of said biasing means to a second position and to hold said device in said second position with said motor stalled, means for controlling the energization of said motor, and means operable to cause engagement of said clutch a predetermined period of time after said motor has been energized and to maintain such engagement during the period said motor is stalled until said motor is deenergized.

9. In combination, an electrical motor, a device to be operated thereby, means biasing said device to a rst position, means including a clutch for connecting said motor and said operating device, said motor being effective when energized and when said clutch is engaged to move said device against the action of said biasing means to a second position, means for controlling the energization of said motor, and means including'a heat motor operative a predetermined period of time after said motor has been deenergized to disengage said clutch and permit said biasing means to move said device back to said first position independently of said motor.

10. In combination, an electric motor comprising electrical windings, a stator, and a rotor; a device to be operated by said motor; means biasing said device to a first position; means including a clutch for connecting said motor and said device, said clutch comprising two cooperating elements one of which is connected to the rotor and which the rotor tends to move into engagement with the other element upon energization of said electrical windings; said motor being effective upon continued energization theerof to cause .engagement of said clutch, to move said device against the action of said biasing means to a second position, and to hold said device in said second position; and means operative a predetermined period of time after deenergization of said motor to disengage said clutch and permit said biasing means to move said device back to said first position independently of said motor.

11. In combination, an electric motor comprising electrical windings, a stator, and a rotor; a device to be operated by said motor; means biasing said device to a first position; means including a clutch for connecting said motor and said dcvice, said clutch comprising two cooperating elements one of which is connected to the rotor isis and which the rotor tends to move into engagement with the other element upon energization of said electrical windings; said motor being eiective upon continued energization thereof to cause engagement of said clutch, to move said device against the action oi' said biasing means to a second position, and to hold said device in s aid second position; and means including a heat motor operative after deenergization of said motor to disengage said clutch and permit said biasing means to move said device back to said first position independently of said motor.

WILLIAM J. MCGOLDRICK. 

